Nucleotides are low molecular weight intracellular compounds
which play key roles in nearly all biochemical processes [4].
The modulatory effects of dietary nucleotides on lymphocyte
maturation, activation and proliferation, as well as macrophage
phagocytosis, immunoglobulin responses and genetic expression
of certain cytokines have been reported in humans and animals [4].
Research pertaining to nucleotide nutrition in fish was stimulated
by the reports of Burrells et al. [1,2], which indicated enhanced
resistance of salmonids to viral, bacterial and parasitic infections
as well as improved efficiency of vaccination and osmoregulation
capacity. Dietary nucleotide supplementation has been shown
to enhance immune responses and disease resistance of tilapia [5],
Atlantic salmon [2], hybrid striped bass [6] and grouper [7].
Supplementation of nucleotides was also reported to enhance
growth of certain fish species (reviewed in [8]).